Dental instrument.



THOMAS DAY CRAIG, F ALBIA, IOWA.

DENTAL INSTRUMENT.

Specification of Letters Patent.

Patented se t.15, 1914.

Application filed January 17, 1914. Serial No. 812,791.

To all whomct may concern: p i v I Be it known that I, THoMAsDAr CRAIG,a citizen of the United States of America, residing at Albia, inthecounty of Monroe and State'of Iowa, have invented certain new anduseful Improvements in Dental Instruments, of which the following" is aspecification. 1

The present invention relates to improvements in dental instruments, andis designed especially for use in the removal ofcrowns, bridges, bands,and all; artificial surfaces 7 affixed to teeth.

forth and claimed hereinafter;

vice.

In the accompanying drawings Iv have illustrated one complete example ofthe physical embodiment of my inventionv constructed according to thebest mode I have so far devisedfor, the practical application of theprinciples ofmyinvention.

While I have herein illustrated the instrument as adaptedfor removingacrown from a tooth, and shall describe only this one feature of thedevice, it will of course be un derstood that the device is capable ofuse in 40 many other ways in dentistry which need notbe described atthis time. s i a s Figure 1 is a side elevation of an instrumentconstructed according to my invention.

Fig. 2 is a plan viewof Fig.1. a Fig. 3 is what mightbe termed a frontend elevation .of the instrumentshowing its application to a toothcrownbeforeremoval of the crown. F ig. 4a is a underside plan view ofthe actuating lever for withdrawing the crown from the tooth. Fig. 5 isa perspective view of ,oneofthemovablejclampingjaws of the dei Fig. *6"is an enlarged view of the swwiwhkh f r s t pivot f r that-W0 movementsof the clamping jaws, showing n'addit-ion a retaining screw for theactuat lnglever. Fig, 7 is a perspective view of one of the heads of thedevice.

i In the preferred embodiment of my invention as exemplified in thedrawings I have utilized the principles of the common type of pliersorscissors in the pivoted handles 1 and 2 of whlchthe screw or threadedpin 3 forms thecouplingmember. In Fig. 6 it will be seen that the pin 3is formed with an annular disk etadapted to be seated in a recess inthelever arm 2, and is further pro vided with a spherical head or ball 5with a kerf G'thereinL and an annular groove 7 'between the head anddisk as will be described.

The two levers 1 and 2 in addition tobeing .operableby hand, areprovided with'a power operating device comprising the piv otedscrew bar8"which is swiveled at 9 in the lever arm 1 and is passed throughan en-,larged opening in the lever arm 2 and provided with a'thumb nut' lOadapted to bear upon the outer face of the lever arm 2 when drawing thetwo arms together.

. The short arms of thelevers 1 and i2 are provided with duplicate heads11 and12, an

gularly disposed and depending from the leversv at a spaced distanceinorder to pro,- vide an opening 13 of considerable size for convenienceof the operator. Each of the heads -is providedwith a dovetail groovel lextending from endsto end of the'head and open at top and bottom, andthese grooves tionof thedevice. I I

, As seenclearly in Fig. 5 the movable jaws orclutches are metalbarsT-shape in cross section crowned witha spherical head or. ball 16and' formed with outwardly'curved lower fingers 17 between whichthetooth crown is to be 1 clutched and then removed. I

., Thejaws 15 are slidable in the mortises of the heads of the leverarms and they are (I moved by means of the springpressed actuatingleverv 18 whichis fulcrumed by means of the socket 19 in the arm overthe ball or head 5 of the pivot screw 3. A set or retaining screw 20(Fig. 6) is threaded into an opening in the lever 18 and engages in theannular groove 7 of the pinto lock the lever 18 against displacementfrom its fulcrum 5, but permits free leverage movement of the lever. Thelever 18 is connected to the heads 1 of the jaws 15 through the mediumof the separated grooves 21 formed in the forks 22 of the lever 18, andin Fig. 1 it will be seen that these grooves are on a circumferencestruck from the socket 99 as a center, and that, when required, thelever 18 may be swung laterally upon the ball 5 as a pivot, as whenattaching or detaching the lever 18 from the device.

The actuating lever 18 is operated or moved on its pivot 5 by means of athumb nut 23 on the swiveled stem 24: which is passed through an opening25 in the end of the lever, and it will be seen in Figs. 1 and 2 thatthis stem is provided with a tubular T-head or "sleeve 26, slipped overthe screw bar 8 and through which the screw bar 8 is free to move. Inthis manner the actuating lever is anchored on the screw bar of thelever arms,'but the parts may be easily detached from each other whendesired.

' From the above descriptiontaken in connection with the drawings it isevident that the instrument is capable of two distinct movements i. e.the clamping of the grasping jaws on the tooth and then the pulling orsliding movement of the engaged clutch fingers 17 to withdraw the crownfrom the tooth. The former of these movements is accomplished by drawingthe two lever arms 1 and 2' together by means of the nut wing, into theposition of Fig. 8 to grip the tooth as in a vise and form an anchor orsupport for the further movements ofthe operative parts of the device.The slidable jaws or clutches are shown in just the proper position todislodge the crown, and this dis lodgment is accomplished by means ofthe actuating lever 18, which, through turning its wing nut is moved onits fulcrum and causes the slidable jaws to be moved and guided throughthe slotted .heads of the levers 1 and 2, and the fingers or claws ofthe slidable jaws engaging under the crown draw the crown fromengagementwith the tooth. The vise or clamping jaws may then beloosenedand the instrument withdrawn from the mouth carrying the dislodged crownwith it as will be readily understood. I do not wish to be understood aslimiting myself to the precise constructions illustrated, as changes maybe made within the scope of my claims without departing from the spiritof myfinvention. As for instance the shape of the slidable jaws andtheir clutching time ma be changed, or other additional jaws ma beprovidedto constiftutea set adapted for interchangeable use. The shapeand size of the mortise and tenon construction may also be varied ifdesired, and other colorable change and modifications'are contemplatedin the physical embodiment of my invention.

Special attention is directed to the ball and socket fulcrum of theactuating lever by means of which the lever is permitted to have afreedom of movement onits fulcrum to adjust itself when operating topull the crown from the tooth, and the feature involving the sphericalheads on the slidable jaws having their connection with the actu atinglever through the round grooves in the lever head or forks is especiallymeritorious for facilitating attachment and removal of the actuatinglever in addition to coupling the jaws with the lever ends.

The grooves 21 are shaped to fit the round heads 16 so that the headsare not likely to pull out and can be taken out only at either side ofthe head.

Having thus fully described my invention, what I claim is 1. Thecombination in a dental instrument havingpivoted lever arms and spacedangular depending heads thereon, of movable clutching jaws in saidheads, and means for moving said jaws, for the purpose described.

2. The combination with a pair of pivoted arms having spaced angulardepending heads, of clutching jaws movable in said heads, and a levermechanism for moving said jaws as described.

p 8. The combination with a pair of lever arms formed'with headsapproximately at right angles thereto, slidable clutching jaws in saidheads, a pivot for said arms, and a lever to actuate said jaws havingits fulcrum on said pivot.

d. The combination with a pair of lever arms formed with heads atapproximately right angles thereto, slidable jaws in' said heads, apivot for said arms having a fulcrum head, and an actuating lever forsaid jaws having asocket and interlocked with said fulcrum head.

5. The combination with a pair of lever arms formed with slotted headsat approximately right angles thereto, slidable jaws in said heads, anda pivot for said arms having a fulcrum head and annular groove, of anactuating lever having a socket over said fulcrum head, and a retainingpin engaging said groove. I

6. In a dental instriunent, the combination with clutching jaws movablewith relation to the instrument, an actuating lever for said jaws, and aball and socket fulcrum connection between said lever and instrument.

7. In a'dent'a-l instrument, the combination with. pivoted lever armshaving heads at approximately right angles thereto, clutching jawsmovable in said heads, and coupling heads on said jaws, of an actuatinglever having a slotted head operatively engaging said coupling heads.

8. In a dental instrument, the combination with pivoted lever armshaving mortised' heads at approximately right angles thereto, clutchingjaws slidable therein and having tenons, and spherical coupling heads onsaid jaws, of a fulcrumed, actuating lever having a forked end and theforks having separated slots embracing said heads as described. a

9. The combination in a dental instrument having pivoted lever arms andspaced heads at approximately right angles thereto thereon, a screw barhinged to one arm and passed through an opening in the other arm and awing nut on said screw bar, slidable clutching jaws in said head, aspring pressed perforated actuating arm for moving said 20 clutchingjaws, a screw bar attached to the first mentioned screw bar and passedthrough said actuating arm, and a thumb nutthereon bearing against saidarm.

In testimony whereof I afiix my signature 25 Copies of this patent maybe obtained for five cents each, by addressing the Commissioner of.Patents,

Washington, D. G.

